Feige has just confirmed Thanos is in GotG and is the mastermind of the events in that movie. Also he says they have very big plans over a long period of time. He mentions that Thanos will be a part of other Marvel films too.

Which films do you think Thanos plays a part in? What do you think the plans for him are? Sound off

I think he plays a part in Thor TDW, Avengers: AoU of course, he could have a role in a Strange film and would make perfect sense to have him play a big part in a Captain Marvel film.

He definitely plays a role in GOTG; Feige has confirmed it. And that's always been obvious.

And I don't see how TDW could sweep him under the rug, since the movie will likely have to address his existence from the very start. Loki's going to be on trial, and he's going to have to answer the question that Thor posed to him in TA1: "Who gave you this knowledge/power?" And there's that whole thing about Thanos' threat/promise to hunt Loki down.

AoU....I no longer believe Thanos will have any presence in TA2 at all. It's still possible, but a lot more remote. Ultron is a terrestrial threat.

After AoU....who knows. I hope GOTG becomes so hugely popular that Marvel will be forced to re-up for a Phase III sequel, and you'd certainly expect to see him come back for that.